CVE-2020-3645
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedFirmware will hit assert in WLAN firmware If encrypted data length in FILS IE of reassoc response is more than 528 bytes in Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wired Infrastructure and Networking in IPQ6018, IPQ8074, Kamorta, Nicobar, QCA6390, QCA8081, QCN7605, QCS404, QCS405, QCS605, Rennell, SC7180, SC8180X, SDA845, SDM670, SDM710, SDM845, SDM850, SM6150, SM7150, SM8150, SXR1130, SXR2130
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA buffer length validation vulnerability exists in Qualcomm WLAN firmware where the FILS IE (Fast Initial Link Setup Information Element) processing in reassoc response packets does not properly validate encrypted data length. When the encrypted data exceeds 528 bytes, the firmware triggers an assertion failure causing the Wi-Fi subsystem to crash or become unstable.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Qualcomm Wi-Fi chip in your deviceCheck your device documentation, FCC labeling, or use commands like 'lspci', 'iw list', 'cat /proc/net/wireless', or vendor-specific commands to list wireless hardware. Look for chip identifiers such as Ipq6018, Ipq8074, Kamorta, Nicobar, Qca6390, Qca8081, Qcs404, or Qcs405.Affected if The device uses any of the listed Qualcomm chip models (Ipq6018, Ipq8074, Kamorta, Nicobar, Qca6390, Qca8081, Qcs404, Qcs405)
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Check the installed WLAN firmware versionUse vendor-specific commands such as 'cat /sys/firmware/wlan/fw_version', 'wlanutil -v', or check the device management interface for firmware version information. Compare the version against the affected product list.Affected if The device runs on any firmware version of the listed Qualcomm chips, as all versions are affected
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Determine if FILS (Fast Initial Link Setup) is enabledCheck wireless configuration files, access point settings, or use 'iw' commands such as 'iw list' to look for FILS support flags. Review 802.11ax (Wi-Fi 6) configuration profiles for FILS enablement settings.Affected if FILS IE processing is enabled and the device participates in FILS authentication/association exchanges
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Monitor for Wi-Fi subsystem crashes or instabilityReview system logs (dmesg, /var/log/messages, vendor-specific logs) for patterns of Wi-Fi driver assertion failures, unexpected disconnections, or firmware crash dumps. Look for timestamps correlating with reassoc response processing.Affected if The Wi-Fi subsystem exhibits crashes, assertion failures, or instability following FILS-enabled reassociation events
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Check for large FILS encrypted data in reassoc responsesCapture wireless traffic using tcpdump, Wireshark, or airmon-ng on the AP/STA interface. Filter for reassoc response packets and examine the FILS IE encrypted data length field. Look for values exceeding 528 bytes.Affected if Reassoc response packets contain FILS IE with encrypted data exceeding 528 bytes
A device is affected if it uses any of the listed Qualcomm Wi-Fi chip models (Ipq6018, Ipq8074, Kamorta, Nicobar, Qca6390, Qca8081, Qcs404, Qcs405) with FILS enabled and processes a reassoc response with encrypted data exceeding 528 bytes, leading to assertion failures.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor firmware updates from Qualcomm or device manufacturers once available. In the interim, network segmentation and monitoring for Wi-Fi connectivity issues may provide limited risk mitigation.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3645 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3645 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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